Re: SCSI tape problem

["Michael L. Hitch" <mhitch%msu.oscs.montana.edu@localhost>]

Ignatios Souvatzis <ignatios%theory.cs.uni-bonn.de@localhost> writes: 
> Stefan Hensen wrote:
> 
> > The harddisks and the CD-ROM work without problems. But when I try to write
> > or read data to/from a tape with commands like 'tar', 'dump' or 'dd', I
> > always get error messages like
> >   tar: can't write to /dev/rst0 : Input/output error
> > or
> >   tar: read error on /dev/rst0 : Input/output error,
> > respectively, and at the same time the following kernel error message
> > appears on the console and in the messages logfile:
> >   st0: bad request, must be between 33925 and 16777215
> 
> Hm... looks like the tape can only use variable block sizes in certain ranges.

  The block limits seem rather strange - I'd suspect they are probably
garbage.  The buffer for the block limits doesn't appear to be cleared
and the actual length of the data returned doesn't appear to be checked,
so it's possible that those values are garbage left on the stack.  More
likely, the buffer is not on a long word boundary and is six bytes long,
and I suspect the driver is not getting the DMA data transferred properly.

Michael
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Michael L. Hitch                        mhitch%montana.edu@localhost
Computer Consultant,  Information Technology Center
Montana State University, Bozeman, MT     USA